261636025 has 12 divisors (see below), whose sum is σ = 370775872. Its totient is φ = 179407440.

The previous prime is 261636013. The next prime is 261636029. The reversal of 261636025 is 520636162.

It is not a de Polignac number, because 261636025 - 2⁹ = 261635513 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (261636029) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 747357 + ... + 747706.

Almost surely, 2^261636025 is an apocalyptic number.

261636025 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

261636025 is a deficient number, since it is larger than the sum of its proper divisors (109139847).

261636025 is a wasteful number, since it uses less digits than its factorization.

261636025 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1495080 (or 1495075 counting only the distinct ones).

The product of its (nonzero) digits is 12960, while the sum is 31.

The square root of 261636025 is about 16175.1669234045. The cubic root of 261636025 is about 639.5863415798.

The spelling of 261636025 in words is "two hundred sixty-one million, six hundred thirty-six thousand, twenty-five".